Re: buffer advisor

Really? I have run into a few situations where the advisor undersizes the buffer cache significantly in favor of the shared pool because of the workload of the application.
I've got a db right _now_ that has a 128MB buffer cache and a 20GB shared pool that AMM resized because of the workload :)

Obviously, the solution to this is to set floor (minimum) values for shared_pool_size and db_cache_size but it still amazes me that ASMM/AMM will significantly undersize the buffer cache when the workload uses a lot of SQL that isn't reuseable.

And I clearly recognize that the workload is suboptimal (lots of SQL with literals and a few other things) that favor a large shared pool, and my only point is that it isn't uncommon for the automatic memory resizing to size the buffer cache to an absurd size :)

Chris

On Thu, Sep 4, 2014 at 4:56 PM, Seth Miller <sethmiller.sm_at_gmail.com> wrote:

> Ls,
>
> I have found with very few exceptions that ASMM (SGA_TARGET) is very good
> at sizing the buffer cache. Have you tried this?
>
> Seth Miller
> On Sep 4, 2014 3:38 PM, "Ls Cheng" <exriscer_at_gmail.com> wrote:
>
>> Hi all
>>
>> Has anyone used buffer cache advisory in 10g or 11g to size a production
>> buffer cache? If so how good is the advisor recommending the cache size?
>> Did the recommended cache size meet the ohysical reads reduction goal?
>>
>> TIA
>>
>>
>>

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